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How do you guys tune your Edelbrocks?

6K views 57 replies 14 participants last post by  rifraf 
#1 ·
My 1406, 625 CFM, has a black film on the top of it, and my friend next door said it was running rich. But I can't smell any gas in the
exhaust.
I've got the idle screws set from 1 1/2 turns, down to 1 turn each.

I'm still trying to get the timing worked out, but I would like to have the carb set right first.

Anything else you think I should do to it, let me know.

Thanks.:thumbup:
 
#2 ·
buy a holley or a demon. or i suppose you could try tuning what you have ;) to tune you have to do much more than play with the screws, those are only for the idle circuit. you need to change the metering rods. I haven't messed with edelbrocks but im assuming they have primary jets? if so you need to go to smaller jets. I love how they say they are pre set and you bolt it on and go. If they do thats fine but if they dont its usually harder to adjust them than a holley. good luck.

by the way isnt a 1406 a 600 cfm? :confused:
 
#3 ·
Yea I know about the metering rods, but I don't know if I would need to change them.


Hehehe, you are right, "easy bolt on" or "works right out of the box" is a oxymoron.


I'm not sure if it is a 600 or 625 but I think Edelbrocks site said it was a 625.
And I NEVER found any info on adjusting it on that site.
 
#4 · (Edited)
From my experience it varies from carb to carb. The very first thing that you need to do is make sure the timing is correct. Then worry about the carb. Read the manual that came with the carb and figure out what jets and rods you should be running for your elevation and driving conditions. Read the manual CAREFULLY as it gives you lots of tips as to various things that might be happening, surging, flat spots etc., and how to adjust for them. Make sure that the carb is mounted properly with the right adapter if needed. You CAN NOT use an open bore manifold or adapter, you have to use the adapter with the 4 individual holes or an edelbrock intake or similar. Make sure that your vacume lines are connected correctly and not leaking, run a vacume test on it. You SHOULD run a heat insulating gasket on it as they tend to get VERY hot under normal driving. You actually need to play with it some to make it work as well as it can. I currently have 2 vehicles that I have them on. One a 1 ton Chevy fire vehicle that an edelbrock was put on and it runs great as is and my personal truck a half ton chevy that I'm still playing with after several weeks of off and on adjustments. You can also get "some" help from Edelbrock. The first tech I talked with was an IDIOT and his solution was that no vehicle with a carb would run in the conditions I drive and I should have bought something with EFI, however their Tech manager sent my e-mail to a different tech "PJ" who knows what he's talking about and really seems to care that I spent money on one of their products and was having problems with it. Good luck to ya.
 
#5 ·
where is it dirty at? what color is the smoke when you floor it at about 25 mph, I can ask around i have a few friends that have rebuilt edelbrocks. Its about as fun as rebuilding a q-jet. basically the same thing except square-bore. try to get light grey smoke when at wot. if its a black puff your rich on your secondaries.
 
#7 ·
mtncat said:
From my experience it varies from carb to carb. The very first thing that you need to do is make sure the timing is correct. Then worry about the carb. Read the manual that came with the carb and figure out what jets and rods you should be running for your elevation and driving conditions. Read the manual CAREFULLY as it gives you lots of tips as to various things that might be happening, surging, flat spots etc., and how to adjust for them. Make sure that the carb is mounted properly with the right adapter if needed. You CAN NOT use an open bore manifold or adapter, you have to use the adapter with the 4 individual holes or an edelbrock intake or similar. Make sure that your vacume lines are connected correctly and not leaking, run a vacume test on it. You SHOULD run a heat insulating gasket on it as they tend to get VERY hot under normal driving. You actually need to play with it some to make it work as well as it can. I currently have 2 vehicles that I have them on. One a 1 ton Chevy fire vehicle that an edelbrock was put on and it runs great as is and my personal truck a half ton chevy that I'm still playing with after several weeks of off and on adjustments. You can also get "some" help from Edelbrock. The first tech I talked with was an IDIOT and his solution was that no vehicle with a carb would run in the conditions I drive and I should have bought something with EFI, however their Tech manager sent my e-mail to a different tech "PJ" who knows what he's talking about and really seems to care that I spent money on one of their products and was having problems iwth it. Good luck to ya.


Well you would be proud of me.:D I got the truck with the carb on it and with no manual. it came with one of those "open" adapters,
but I saw right away how bad it would flow with an open adapter,
so I got me a 4 holer.

Oh and there is a very small flat spot at mid range, but it is not a big problem to me.
And there is no black smoke from the pipes. and the exh does not smell rich at idle.
 
#9 ·
My old one used to get that film and my jets were dead on perfect,they will do that,its not a bad sign necessarily. If it runs good,just use a shot of carb cleaner once in awhile and go with it. I do like a Demon better though. Your dead spot is most likely a lean condition on the secondaries,up one size would probably cure it.
 
#10 ·
OK, you guys got me all hysterical now as I look at the new 1406 edelbrock (600 cfm) sitting here on the table, soon to go on my 350 SBC. Oh well, live and learn I suppose. I always thought that edelbrock made a fairly decent carb.

Tuning Procedure:

http://www.edelbrock.com/automotive/index.html

Edit/// Above link will not go to specific page. At the link above, select carburetors from the left hand column. Then select Edelprock Performer Carb Owners Manual. See Section 2.
 
#11 ·
They are good,the way they are made just shows the filth more. Don't sweat it,you will be happy with it,its only luck if you bolt a carb on and need not play with it to make it perfect,that goes for any carb,usually they are overjeted so they run good but use an unneeded amount of fuel from the box.
 
#12 ·
Magikal,

i just put a new edelbrock 600cfm on my 390, fired right up. after running the cam in, i too noticed a graphite colored film on the top of the carb....no smoke out the exhaust..... but i'm not too concerned with milage, and it runs like a raped ape. i'd have to say i'm happy so far, but i do intend to buy the calibration kit for it, cos oneday, i'll figure out wth to do to fine tune it. i think i might like to go a step lighter on the spring, and a tad less on the metering rod too..... :confused: :p
 
#14 ·
There is no set amount,I would start out about 3 and turn each one in slowly until it just starts to change the idle adversely,then come back out about 1/4 turn,its usually about 2 but the mixture needs are all going to be a little different,those only control your idle circuit.
 
#16 ·
crazy larry said:
you want me to screw mine in and count the turns?:p

and i agree, edelbrocks tech service sucks. online or on the phone.:rolleyes:

Only if you want to.

I got mine set back at 1 1/2 turns. runs fine.


I'm going to find a stock cold air intake tube/air cleaner that my truck had before the last guy replaced it with a crappy chrome one.

And I will be installing a damper cover to get the timing right.
Then I may want to do some more fine tuning to the carb.

Thanks again.
 
#17 ·
My dad taught me long ago the exact same method of tuning carbs that rifraf described previous. It works on any carb of any car of any make and will at least make it driveable without any precision tools required. All by ear. Usually a short drive and a quick stop for a 1/8 turn here or a 1/8 turn there and I have saw many motors run troublefree.

Thanx Dad!!

Old School Rocks!!
 
#19 ·
If you want to tune the idle screws the best way as i have found is to use a vacume guage..
set your screws up to 1 1/2 turns,hook the vacume guage to manifold vacume then adjust them one at a time watch the vacume guage when the vacume peaks, back off the screw 1/4 turn, then move to the next screw..
This way always worked for me and set them up perfect.
 
#22 ·
The point is...the higher the vacuum, the better. That vacuum guage that you have in the cab, is for the purpose of getting better mileage. The higher you keep it while driving, the better the mileage. You will notice, when you mash the gas, it goes down to "0"
 
#24 ·
Just turn the screws in and out to get the highest number without it varying,no less,no more,go back and forth a little to be sure and do it slowly so the motor has enough time to react. That vacuum gauge is also an awesome tool for timing your rig,I would take it over a light any day,you can use it for a lot of stuff,they are a good tool to have.
 
#26 ·
I would like to hear your answer also rifraf....

I heard somewhere that you can time it to max vaccuum and back off about 1 in mg, but when I tried this on my newly rebuild engine, my initial timing was way over 20 BTDC and I didn't think that was right.

Let us know because I am very curious.
 
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